The international market is going through a period of flux, as forces that have been bubbling away for years gradually twist the industry into different shapes. Looking at the results from this year's Global 100 gives some indication of how this is playing out, but the patterns are still far from set.

There is a growing push for firms outside the top tier to achieve real scale fast – as typified by international moves from Norton Rose, Ashurst and Hogan Lovells. Certainly, there is an increasing premium being placed on scale. Whether articulated or not, a common aspiration among many major firms in the UK is to secure a good position in the global top 50 by revenue.

A huge complication is the desire among both European and US firms to secure major transatlantic mergers while remaining the top dog – or at least equal partner. Ashurst/Blake Dawson was as much a product of the UK firm's desire to not be subsumed by a larger US suitor.

Likewise, Norton Rose's rapid expansion is based in part on a desire to have a stronger position when it ultimately comes to securing a US merger. However, the equation remains difficult, as the kind of partner such firms will want to merge with will often want to have the upper hand themselves.

And it's not as simple as going for growth or a consolidation play. The magic circle, with the exception of Allen & Overy (A&O), ditched expansion years ago in favour of highly targeted investment, and there's little sign of that shifting. But in many ways the City's finest have little choice but to guard their profitability jealously – the sustained weakness of the pound and strong performances from a band of expansive, internationally-proactive US law firms means UK firms remain exposed.

Retaining their best people and sustaining progress in key strategic markets will be a challenge. Expect the trend of large City firms ushering in more flexible partnership remuneration to continue for years to come. And while many US firms have written themselves out of the script with timid international ambitions, the US market is so vast that a combination of fast-growing national firms like Kirkland & Ellis and Latham & Watkins and top-tier New York firms like Sullivan & Cromwell and Simpson Thacher & Bartlett will hit the magic circle on different fronts.

Though some will fail, the huge pool of contenders means there remain as many as 25 practices that present a serious threat – a very different dynamic to the magic circle's 'national champion' status.

UK firms must also contend with a future in which their fortunes will be less generously assisted by the growth of London as a finance centre, as has happened over the last decade. There have been some smart moves from UK leaders and not many unforced errors since the banking crisis. That's just as well, as the margin for error will be thin over the years to come.